1. Field of the Invention
This invention relates to a printer provided with a paper-feeding mechanism which feeds recording paper one by one piled in a cassette.
2. Description of Related Art
As a printer of delivering piled recording paper one by one, for example, a printer with a paper feeding unit separating paper with friction rollers is disclosed in Japanese Patent Application Laid-Open No. 59-6442 (1984). As shown in FIG. 1, the printer is provided with a pick up roller 14 which presses on the upper surface of the recording paper piled on a sheet loading plate 19 on a paper-feeding cassette 18 for sending out the uppermost recording paper 20 by rotating correspondingly to a feeding signal, a feed roller 33 which rotates downstream in the feeding direction installed downstream of the feeding direction, and a separation roller 13 which presses on the feed roller 33 with the recording paper passing between them and rotates in the direction of pushing back the recording paper 20. The paper feeding unit is so constructed as to separate one piece of paper to feed due to the difference of coefficients of friction by selecting material of the rollers where the coefficients of friction between the feed roller 33 and the paper, the separation roller 13 and the paper, and one piece of paper and another being respectively represented by .mu.f, .mu.s and .mu.p, satisfy the following inequality; EQU .mu.f&gt;.mu.s&gt;.mu.p
A conventional paper feeding mechanism feeds paper by three rollers, that is, a pick up roller 14 for picking up the recording paper 20 from the paper-feeding cassette 18, a feed roller 33 provided at a downstream side of the pick up roller 14 and sends the recording paper 20 to the body of the recording apparatus, and a separation roller 13 for preventing plural pieces of recording paper 20 being sent at a time. This paper feeding mechanism, however, is independent from the recording apparatus, so that a guide mechanism for guiding the recording paper 20 to the body mechanism is required, resulting in being an obstacle to make the apparatus small-sized.